/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.util.xml;

import org.xml.sax.ContentHandler;
import org.xml.sax.DTDHandler;
import org.xml.sax.EntityResolver;
import org.xml.sax.ErrorHandler;
import org.xml.sax.SAXNotRecognizedException;
import org.xml.sax.SAXNotSupportedException;
import org.xml.sax.XMLReader;
import org.xml.sax.ext.LexicalHandler;

import org.springframework.lang.Nullable;

/**
 * Abstract base class for SAX {@code XMLReader} implementations.
 * Contains properties as defined in {@link XMLReader}, and does not recognize any features.
 *
 * @author Arjen Poutsma
 * @author Juergen Hoeller
 * @see #setContentHandler(org.xml.sax.ContentHandler)
 * @see #setDTDHandler(org.xml.sax.DTDHandler)
 * @see #setEntityResolver(org.xml.sax.EntityResolver)
 * @see #setErrorHandler(org.xml.sax.ErrorHandler)
 * @since 3.0
 */
abstract class AbstractXMLReader implements XMLReader {

    @Nullable
    private DTDHandler dtdHandler;

    @Nullable
    private ContentHandler contentHandler;

    @Nullable
    private EntityResolver entityResolver;

    @Nullable
    private ErrorHandler errorHandler;

    @Nullable
    private LexicalHandler lexicalHandler;


    @Override
    public void setContentHandler(@Nullable ContentHandler contentHandler) {
        this.contentHandler = contentHandler;
    }

    @Override
    @Nullable
    public ContentHandler getContentHandler() {
        return this.contentHandler;
    }

    @Override
    public void setDTDHandler(@Nullable DTDHandler dtdHandler) {
        this.dtdHandler = dtdHandler;
    }

    @Override
    @Nullable
    public DTDHandler getDTDHandler() {
        return this.dtdHandler;
    }

    @Override
    public void setEntityResolver(@Nullable EntityResolver entityResolver) {
        this.entityResolver = entityResolver;
    }

    @Override
    @Nullable
    public EntityResolver getEntityResolver() {
        return this.entityResolver;
    }

    @Override
    public void setErrorHandler(@Nullable ErrorHandler errorHandler) {
        this.errorHandler = errorHandler;
    }

    @Override
    @Nullable
    public ErrorHandler getErrorHandler() {
        return this.errorHandler;
    }

    @Nullable
    protected LexicalHandler getLexicalHandler() {
        return this.lexicalHandler;
    }


    /**
     * This implementation throws a {@code SAXNotRecognizedException} exception
     * for any feature outside of the "http://xml.org/sax/features/" namespace
     * and returns {@code false} for any feature within.
     */
    @Override
    public boolean getFeature(String name) throws SAXNotRecognizedException, SAXNotSupportedException {
        if (name.startsWith("http://xml.org/sax/features/")) {
            return false;
        } else {
            throw new SAXNotRecognizedException(name);
        }
    }

    /**
     * This implementation throws a {@code SAXNotRecognizedException} exception
     * for any feature outside of the "http://xml.org/sax/features/" namespace
     * and accepts a {@code false} value for any feature within.
     */
    @Override
    public void setFeature(String name, boolean value) throws SAXNotRecognizedException, SAXNotSupportedException {
        if (name.startsWith("http://xml.org/sax/features/")) {
            if (value) {
                throw new SAXNotSupportedException(name);
            }
        } else {
            throw new SAXNotRecognizedException(name);
        }
    }

    /**
     * Throws a {@code SAXNotRecognizedException} exception when the given property does not signify a lexical
     * handler. The property name for a lexical handler is {@code http://xml.org/sax/properties/lexical-handler}.
     */
    @Override
    @Nullable
    public Object getProperty(String name) throws SAXNotRecognizedException, SAXNotSupportedException {
        if ("http://xml.org/sax/properties/lexical-handler".equals(name)) {
            return this.lexicalHandler;
        } else {
            throw new SAXNotRecognizedException(name);
        }
    }

    /**
     * Throws a {@code SAXNotRecognizedException} exception when the given property does not signify a lexical
     * handler. The property name for a lexical handler is {@code http://xml.org/sax/properties/lexical-handler}.
     */
    @Override
    public void setProperty(String name, Object value) throws SAXNotRecognizedException, SAXNotSupportedException {
        if ("http://xml.org/sax/properties/lexical-handler".equals(name)) {
            this.lexicalHandler = (LexicalHandler) value;
        } else {
            throw new SAXNotRecognizedException(name);
        }
    }

}
